Heart regurgitation method and apparatus

ABSTRACT

A regurgitation implant may comprise a conduit or straw which may be coupled to a shaft. The shaft may be coupled to at least one anchor portion configured to couple the regurgitation implant to native coronary tissue. At least a portion of the conduit may be configured to be disposed proximate a mitral valve such that the regurgitation implant may interact and/or cooperate with at least a portion of the native mitral valve to induce a controlled amount of regurgitation through the conduit and therefore through the mitral valve. The regurgitation through the conduit and the mitral valve may cause the heart to dilute in a manner that is generally consistent with advanced disease of the heart. The amount of regurgitation may therefore be adjusted depending on the desired condition of the heart.

FIELD

The present disclosure relates to diagnosing dysfunctional heart valves,and more particularly pertains to heart regurgitation methods andapparatus.

BACKGROUND

A human heart has four chambers, the left and right atrium and the leftand right ventricles. The chambers of the heart alternately expand andcontract to pump blood through the vessels of the body. The cycle of theheart includes the simultaneous contraction of the left and right atria,passing blood from the atria to the left and right ventricles. The leftand right ventricles then simultaneously contract forcing blood from theheart and through the vessels of the body. In addition to the fourchambers, the heart also includes a check valve at the upstream end ofeach chamber to ensure that blood flows in the correct direction throughthe body as the heart chambers expand and contract. These valves maybecome damaged, or otherwise fail to function properly, resulting intheir inability to properly close when the downstream chamber contracts.Failure of the valves to properly close may allow blood to flow backwardthrough the valve resulting in decreased blood flow and lower bloodpressure.

Mitral regurgitation is a common variety of heart valve dysfunction orinsufficiency. Mitral regurgitation occurs when the mitral valveseparating the left coronary atrium and the left ventricle fails toproperly close. As a result, upon contraction of the left ventricleblood may leak or flow from the left ventricle back into the leftatrium, rather than being forced through the aorta. Any disorder thatweakens or damages the mitral valve can prevent it from closingproperly, thereby causing leakage or regurgitation. Mitral regurgitationis considered to be chronic when the condition persists rather thanoccurring for only a short period of time.

Regardless of the cause, mitral regurgitation may result in a decreasein blood flow through the body (cardiac output). Correction of mitralregurgitation typically requires surgical intervention. Surgical valverepair or replacement is carried out as an open heart procedure. Therepair or replacement surgery may last in the range of about three tofive hours, and is carried out with the patient under generalanesthesia. The nature of the surgical procedure requires the patient tobe placed on a heart-lung machine. Because of theseverity/complexity/danger associated with open heart surgicalprocedures, corrective surgery for mitral regurgitation is typically notrecommended until the patient's ejection fraction drops below 60% and/orthe left ventricle is larger than 45 mm at rest.

Although mitral regurgitation is present in a many human patientsthroughout the world, there are far less known instances of the diseasein typical animal test species. As such, there is no known reliablesources for naturally occurring congestive heart failure animal modelsfor the purposes of testing efficacy of a given therapy. Most efficacytest models rely on some type of surgical intervention to compromise theheart function of the test specimen prior to application of the testtherapy and these interventions introduce many co-morbidities into theexperiments as a result of the initial surgery.

BRIEF DESCRIPTION OF THE DRAWINGS

Features and advantage of the claimed subject matter will be apparentfrom the following description of embodiments consistent therewith,which description should be considered in conjunction with theaccompanying drawings, wherein:

FIG. 1 is a perspective view of one embodiment of a regurgitationimplant;

FIG. 2 depicts another embodiment of a regurgitation implant including aplurality of conduits;

FIG. 3 depicts yet another embodiment of a regurgitation implant;

FIG. 4 depicts one embodiment of a regurgitation implant implantedwithin a heart in an open position; and

FIG. 5 depicts the regurgitation implant of FIG. 4 implanted within aheart in a closed position;

DESCRIPTION

Referring to FIG. 1, a perspective view of one embodiment of aregurgitation implant 10 for inducing a controlled regurgitation in aheart valve (for example, a mitral heart valve) is shown. Theregurgitation implant 10 may generally include a conduit or straw 12which may be coupled to a shaft 14. The shaft 14 may be coupled to atleast one anchor portion 16 configured to couple, attach, and/orotherwise secure the regurgitation implant 10 to native coronary tissue.In general, at least a portion of the conduit 12 may be configured to bedisposed proximate a mitral valve such that the regurgitation implant 10may interact and/or cooperate with at least a portion of the nativemitral valve to induce a controlled amount of regurgitation through theconduit 12 and therefore through the mitral valve. The regurgitationthrough the conduit 12 and the mitral valve may cause the heart todilute in a manner that is generally consistent with advanced disease ofthe heart. The amount of regurgitation may therefore be adjusteddepending on the desired condition of the heart.

The conduit or straw 12 may be configured to provide at least oneopening or passageway through the heart valve when the heart valve is inthe closed position in order to provide the desired amount ofregurgitation. According to one embodiment, the conduit or straw 12 maydefine a passageway 18 having at least a first and a second end 20, 22configured to extend between a first chamber of the heart, through aheart valve, and into a second chamber of the heart. For example, thepassageways 18 may be configured to extend from the left atrium, throughthe mitral valve, and into the left ventricle. According to anotherembodiment, the regurgitation implant 10 may include a plurality ofpassageways 18 as generally shown in FIG. 2. The diameter of thepassageways 18 may be selected to provide the desired amount ofregurgitation flow through the heart valve when the heart valve is inthe closed position.

At least a portion of the conduit or straw 12 may be constructed from asynthetic and/or biological material depending on the application andthe patient condition and may include a plurality of layers. Forexample, the conduit or straw 12 may include an open or closed cell foamsubstrate (for example, but not limited to, Invalon polyvinyl) and anouter layer of a material that is biologically acceptable. The outerlayer may also include a material that is soft and/or deformable (eitherpermanently or resiliently deformable) that may reduce and/or eliminatefurther scarring and/or damage to the leaflets of the valve. Accordingto one aspect, the substrate of the conduit or straw 12 may be coatedwith or formed substantially from a silicone urethane composite such as,but not limited to, Elasteon or the like.

According to one embodiment, the conduit or straw 12 may include astent-like structure. For example, the conduit or straw 12 may include aframe (for example, a helical frame, braided frame, interconnecting rowframe, or hatched frame) that may define a generally cylindricalstructure configured to provide at least one opening through the heartvalve when the heart valve is in the closed position. The conduit orstraw 12 may optionally include a substrate such as, but not limited to,polytetrafluoroethylene (PTFE), disposed about at least a portion of theframe of the conduit or straw 12. The substrate may also include acoating or layer (for example, a coating or layer of PTFE) disposedabout the inner and/or outer surfaces of the conduit or straw 12.According to another embodiment, the conduit or straw 12 may include agenerally tube-like structure. For example, the conduit or straw 12 mayinclude a generally tube-like structure made from PTFE.

At least a portion of the conduit or straw 12 may be collapsible and/orexpandable. The conduit or straw 12 may be configured to fit through thelumen of a catheter or the like when collapsed to facilitate delivery ofthe regurgitation implant 10 to the heart. According to one embodiment,the conduit or straw 12 may include a self-expanding metallic stent(SEMS). The SEMS may include a shape-memory alloy such as, but notlimited to, copper-zinc-aluminum, copper-aluminum-nickel, andnickel-titanium (NiTi) alloys, polyurethane, and polyethylene. Theshape-memory alloy may include either one-way or two-way shape memoryand may be introduced in to the delivery catheter lumen (not shown)having a shape which does not exceed the interior dimensions of thedelivery catheter lumen. The conduit or straw 12 may also include aplastic self-expanding stent (such as, but not limited to, Polyflex®made by Boston Scientific). The conduit or straw 12 may also beexpandable through use of a balloon or the like. For example, one ormore fluids (gases and/or liquids) may be provided to inflate theconduit or straw 12 from the collapsed position to the expandedposition.

The conduit or straw 12 may be mounted, coupled, or otherwise secured toat least part of the shaft 14. For example, the conduit or straw 12 maybe generally disposed along a portion of the shaft 14 as shown in FIGS.1 and 2. The shaft 14 may extend beyond the ends 20, 22 of the conduitor straw 12 as generally shown in FIG. 1 and may optionally includebushing or the like 24 disposed about the distal-most end of the shaft14. The bushing 24 may optionally include a driver configured to engagewith a clamping mechanism as generally described in co-pending U.S.patent application Ser. No. 11/940,694 (Attorney Docket: CAR023), whichis fully incorporated herein by reference. According to anotherembodiment, the shaft 14 may terminate at or before the distal-most endof the conduit or straw 12 as generally shown in FIGS. 2 and 3.

The conduit or straw 12 may be coupled to at least a portion of theshaft 14 by way of an adhesive or cement (such as, but not limited to, abiologically acceptable adhesive or cement), bonding/molding (such as,but not limited to, overmolding and the like), or welding (such as, butnot limited to, ultrasonic welding or the like). The conduit or straw 12may also be coupled to at least a portion of the shaft 14 using afastening mechanism. The fastening mechanism may substantially fix theposition of one or more of the conduit or straw 12 with respect to theregurgitation implant 10 (and specifically with respect to the shaft14). According to another aspect, the fastening mechanism may allow oneor more of the conduits or straws 12 to move relative to the shaft 14.For example, the fastening mechanism may allow the one or more of theconduits or straws 12 to move generally along the longitudinal axisand/or radially with respect to the shaft 14.

Turning now to FIG. 4, one embodiment of a heart 60 is shown in acondition in which the pressure of blood within the left atrium 62 is atequal to, or higher than, the pressure of blood within the leftventricle 64, e.g., during contraction of the left atrium 62. As shown,when the pressure of blood within the left atrium 62 is greater than orequal to the pressure of blood within the left ventricle 64, blood mayflow from the left atrium 62 into the left ventricle 64. In the openposition, the pressure differential causes a flow of blood from the leftatrium 62 to the left ventricle 64. Additionally, the flow of blood fromleft atrium 62 to the left ventricle 64 may cause the mitral valve 61 toflare and/or expand outwardly away from the mitral valve implant 10. Theregurgitation implant 10 may provide sufficient clearance between themitral valve 61 and the conduit or spacer 12 to permit adequate bloodflow from the left atrium 62 to the left ventricle 64. Some of the bloodmay also flow through the regurgitation implant 10 as generallyindicated by the arrows.

As the left ventricle 64 contracts, the pressure of blood in the leftventricle 64 may increase such that the blood pressure in the leftventricle 64 is greater than the blood pressure in the left atrium 62.Additionally, as the pressure of the blood in the left ventricle 64initially increases above the pressure of the blood in the left atrium62, blood may begin to flow towards and/or back into the left atrium 62.

In the closed position as shown in FIG. 5, at least a portion of theconduit or straw 12 may interact with, engage, and/or be positionedadjacent to at least a portion of the mitral valve 61. For example, atleast a portion of at least one cusp 63 of the mitral valve 61 maycontact at least a portion of the conduit or straw 12. Engagementbetween the conduit or straw 12 and the mitral valve 61 may generallyrestrict the flow of blood from the left ventricle 64 back into the leftatrium 62. In addition to restricting the flow of blood from the leftventricle 64 to the left atrium 62, the regurgitation implant 10 mayinduce a controlled amount of regurgitation through the conduit or straw12 and therefore through the mitral valve 61 as generally indicated bythe arrows. The inducement of regurgitation through the mitral valve 61may cause the heart 60 to dilate in a manner that is generallyconsistent with heart disease.

The regurgitation implant 10 may be inserted in the heart 60percutaneously (for example, by way of a catheter-based delivery systemas generally described in co-pending U.S. patent application Ser. No.11/258,828, entitled “Heart Valve Implant” filed on Oct. 26, 2005, U.S.patent application Ser. No. 11/748,147, entitled “Safety for MitralValve Plug” filed on May 14, 2007, U.S. patent application Ser. No.11/748,138, entitled “Solid Construct Mitral Spacer” filed on May 14,2007, and U.S. patent application Ser. No. 11/748,121, entitled “BallonMitral Spacer” filed on May 14, 2007, all of which are herebyincorporated by reference. The use of the catheter-based delivery systemmay spare the recipient (for example, an animal) from the collateraldamage that may be caused by surgical or drug induced techniques. Theregurgitation implant 10, in and of itself, may not alter the anatomy ofthe valve, but may serve to create a heart output insufficiency that maycause the heart to naturally remodel in a manner the same as or similarto a heart (such as a human heart) suffering from valvularregurgitation.

The regurgitation implant 10 herein has been disclosed above in thecontext of a mitral valve implant. An regurgitation implant 10consistent with the present disclosure may also suitably be employed inother applications, e.g., as an implant associated with one of the othervalves of the heart, etc. The present disclosure should not, therefore,be construed as being limited to use for reducing and/or preventingregurgitation of the mitral valve.

According to one aspect, the present disclosure features an implantcomprising a shaft, at least one anchor coupled to a first end region ofthe shaft, and at least one conduit coupled to the shaft. The conduit isconfigured to interact with at least a portion of at least one cusp of aheart valve to induce a controlled amount of regurgitation through theheart valve in a closed position.

According to another aspect, the present disclosure features aregurgitation implant comprising a shaft, at least one anchor coupled toan end region of the shaft, and at least one conduit coupled to theshaft configured to interact with at least a portion of at least onecusp of a heart valve to at least partially restrict a flow of bloodthrough the heart valve in a closed position. The conduit defines atleast one passageway configured to extend through the heart valve andinduce a controlled amount of regurgitation through the heart valve inthe closed position.

According to yet another aspect, the present disclosure features amethod of inducing regurgitation. The method comprises providing aregurgitation implant including at least one anchor portion and conduitcoupled to a shaft. The implant is percutaneously inserted into a heartand secured within the heart such that the conduit interacts with atleast a portion of at least one cusp of a heart valve to define at leastone passageway through the heart valve configured to induce a controlledamount of regurgitation through the heart valve in a closed position.

As mentioned above, the present disclosure is not intended to be limitedto a system or method which must satisfy one or more of any stated orimplied object or feature of the present disclosure and should not belimited to the preferred, exemplary, or primary embodiment(s) describedherein. The foregoing description of a preferred embodiment of thepresent disclosure has been presented for purposes of illustration anddescription. It is not intended to be exhaustive or to limit the presentdisclosure to the precise form disclosed. Obvious modifications orvariations are possible in light of the above teachings. The embodimentwas chosen and described to provide the best illustration of theprinciples of the present disclosure and its practical application tothereby enable one of ordinary skill in the art to utilize the presentdisclosure in various embodiments and with various modifications as issuited to the particular use contemplated. All such modifications andvariations are within the scope of the present disclosure as determinedby the claims when interpreted in accordance with breadth to which theyare fairly, legally and equitably entitled.

1. An implant comprising: a shaft; at least one anchor coupled to afirst end region of said shaft; and at least one conduit coupled to saidshaft, wherein said at least one conduit is configured to interact withat least a portion of at least one cusp of a heart valve to induce acontrolled amount of regurgitation through said heart valve in a closedposition.
 2. The implant of claim 1, wherein said at least one conduitdefines a passageway extending from a first end to at least a secondend.
 3. The implant of claim 2, wherein said at least one conduitcomprises a stent.
 4. The implant of claim 1, wherein said at least oneconduit comprises a frame.
 5. The implant of claim 4, wherein at least aportion of said frame comprises a layer of polytetrafluoroethylene. 6.The implant of claim 1, wherein at least a portion of said conduit isexpandable.
 7. The implant of claim 6, wherein said expandable portioncomprises an inflatable bladder.
 8. The implant of claim 6, wherein saidexpandable portion comprises a shape memory material configured torecoverably deform.
 9. The implant of claim 1 comprising a plurality ofconduits defining a plurality of passageways configured to induceregurgitation through said heart valve in said closed position.
 10. Theimplant of claim 1, wherein a second end region of said shaft generallyopposite from said first end region extends beyond a distal-most endregion of said conduit.
 11. The implant of claim 10, wherein said secondend region of said shaft comprises a driver configured to engage aclamping mechanism of a delivery system.
 12. The implant of claim 1,wherein a portion of said conduit extends beyond a second end region ofsaid shaft generally opposite from said first end region.
 13. Theimplant of claim 1, wherein said anchor portion include at least onehelical screw.
 14. A regurgitation implant comprising: a shaft; at leastone anchor coupled to an end region of said shaft; and at least oneconduit coupled to said shaft configured to interact with at least aportion of at least one cusp of a heart valve to at least partiallyrestrict a flow of blood through said heart valve in a closed position,wherein said at least one conduit defines at least one passagewayconfigured to extend through said heart valve and induce a controlledamount of regurgitation through said heart valve in said closedposition.
 15. The regurgitation implant of claim 14, wherein at least aportion of said conduit is expandable.
 16. The regurgitation implant ofclaim 15, wherein said expandable portion comprises an inflatablebladder.
 17. The regurgitation implant of claim 15, wherein saidexpandable portion comprises a shape memory material configured torecoverably deform.
 18. A method of inducing regurgitation comprising:providing a regurgitation implant comprising at least one anchor portionand conduit coupled to a shaft; percutaneously inserting saidregurgitation implant into a heart; and securing said regurgitationimplant within said heart such that said at least one conduit interactswith at least a portion of at least one cusp of a heart valve to defineat least one passageway through said heart valve configured to induce acontrolled amount of regurgitation through said heart valve in a closedposition.
 19. The method of claim 18 further comprising: at leastpartially collapsing said regurgitation implant; percutaneouslydelivering said at least partially collapsed regurgitation implantproximate said heart; and expanding said at least partially collapsedregurgitation implant.
 20. A method according to claim 15, whereinpercutaneously inserting said at least partially collapsed regurgitationimplant comprises inserting said regurgitation implant into a lumen of acatheter and delivering said regurgitation implant to said leftventricle via said catheter.